MTBE biodegradation and degrader microbial community dynamics in MTBE, BTEX, and heavy metal-contaminated water

The aim of this investigation was to explore microbial community changes under various environmental groundwater conditions (single substrate, mixed substrates, and the presence of heavy metals) and link the changes with simultaneously diminishing substrate concentration in the microcosms. Most microorganisms from environmental microcosms or wastewater treatment plants cannot be cultivated artificially. Capturing microbial community fingerprints, therefore, requires applying a molecular biological technique. By using SSCP profiles of PCR-amplified 16S rDNA genes, it was demonstrated that with the repeated addition of substrates during long-term acclimation, substrate-utilizing populations in a microcosm gradually increased to become the dominant constituent. Conversely, the presence of metals inhibited community development and differentiation. It was also shown that substrate degradation rates increased under co-substrate conditions, with substrate-degraders easily adapting to the environment and becoming the dominant bacteria, a phenomenon attributed to the propensity of the fittest species to outgrow their competitors when presented with suitable substrates. (c) 2006 Elsevier Ltd. All rights reserved.